Figure 1.

Schematic representation of the experimental procedure. (Experiments 1 and 3) Massed training. The glass tube containing the prey was opened to the view of the cuttlefish for a single presentation of 20 min (gray rectangles). At the end of the 10th minute of training, experimental cuttlefish (groups E₁ and E₃) were given the arousing stimulation (crab: Experiment 1, flashing light: Experiment 3; see arrows). (Experiment 2) Spaced training. Cuttlefish were given eight presentations of the glass tube containing the prey (gray squares), lasting 3 min each, spaced at 30-min intervals (dotted lines). Twenty-nine minutes 30 sec (group E_2-1), 15 min (group E_2-2), or 30 sec (group E_2-3) before the start of the seventh presentation, experimental cuttlefish were given the arousing stimulation (crab, see arrows). (Experiment 4) Fifty-six applications (black squares) of a brief visual prawn stimulus (shrimp). Shrimp were presented seven times (each 30 sec, see arrows) for a period of 3 min, each of eight periods being separated by a rest interval of 30 min (dotted lines).